Pre-landing review (testing + checklist specialists, reproduced) caught a
data-loss bug: cmd_rekey's decrypt/re-encrypt globs were non-recursive and
only special-cased external/. Nested manifest dotenv blobs
(<project>/<relpath>.age, new this branch) were never visited, so after a key
rotation they stayed encrypted under the discarded old key = permanently
undecryptable. cmd_list had the same blind spot (cosmetic: nested entries
invisible in listings).
Both now walk the entire project tree with `find -type f` (bash 3.2 safe,
includes dotfiles natively), unifying top-level / nested / external blobs into
one recursive pass and dropping the now-redundant external/ special-casing.
Regression tests: nested-blob rekey round-trip (survives rotation) + list
shows nested entry. Full suite 193/193.
c6ea724ddb